All About Tires

Everything you need to know

Learn the basics, and then some

Get tire information, tips and advice you need right here. Can’t find the answer you want with the tire information provided? Our tire experts are always available to give you tire information you’re looking for at a store near you.

With regular tire maintenance, you can lower your fuel costs and help protect the environment. Keep an eye on your air pressure (or PSI) to make sure your tires are inflated to the right amount.

Under-Inflated Tires

"Soft" tires make your vehicle work harder. Under-inflation causes excessive sidewall flexing, which reduces not only your vehicle’s carrying capacity but your fuel economy too. If you notice excessive shoulder wear, where the sidewall meets the tread of the tire, it could be a sign of under-inflation.

Over-Inflated Tires

Over-inflation causes the centre of the tire tread to bear most of your vehicle's weight. This leads to faster and more irregular tread wear, and you may have to repair or replace your tires sooner than expected. Inspect your tires regularly for signs of wear at the centre of the tread to make sure they are not over-inflated.

Nitrogen makes up 78% of air. In its purest form, this non-flammable gas can be used for tire inflation without negative environmental impacts.

Air-filled tires lose 1 to 2 pounds per square inch (PSI) of pressure every month. Since a nitrogen molecule is larger than oxygen, it will not seep out as quickly.

Air-filled tires also have more moisture, which contributes to a loss of up to 2 PSI for every 5 degree Celsius drop. Using nitrogen helps prevent this loss because it reduces the amount of water vapour in the tire.

Tires wear out over time. Differences in speed, road conditions, inflation, vehicle maintenance, your driving habits, and temperature make it hard to predict exactly how long your tires will last. We recommend inspecting your tires regularly and replace them when they are worn down.

Here are three ways to measure your tread:

1. Tread Depth Gauge

You can check this yourself with an inexpensive tread depth gauge, available at most auto supply stores. You’ll know to replace your all-season and all-weather tires when there is just 1.6-mm (2/32-inch) tread depth remaining. Winter Tires need a deeper tread to keep traction in the snow. We recommend replacing them when there is just 3.2 mm (4/32 inch) remaining.

2. The Tire Wear Bars

Tires are manufactured with wear bars that indicate when there is less than 1.6 mm (2/32 inch) of tread depth remaining. When the tread is worn down to the point where you can see a solid bar of rubber across the width of the tread, it’s time to replace your tires.

3. The Dime Test

The Rubber Association of Canada suggests this simple test to measure the tread depth on your tires. Place a dime upside down, with the tail of the dime facing you. If you can see the top of the sails of the famous East Coast racing schooner, it is time to replace the tire.

Tread Region: The "flat" area of the tire that you drive on. The construction of the tread will determine the grip of the tire in different weather conditions. It will affect your speed, acceleration, braking, andcornering.

Shoulder and Sidewall Region: The vertical side of the tire that extends from the road surface to the rim. The construction of the sidewall affects the ride and handling of the tire. A stiff sidewall provides quick steering response, while a softer sidewall flexes to provide a smoother ride.

There are three key pieces of information in the numbers moulded in the sidewall of your tire. We’ve broken down an example tire number of P215/65R15 89H below so that you can more easily understand the numbers on your tire and find the right replacement for your vehicle.

Tire Size:

"P" indicates that this tire is made specifically for a passenger car, minivan, CUV, or SUV.

"215" indicates the tire width in millimetres from sidewall to sidewall.

"65" indicates this tire’s percent ratio of height to width.

"R" stands for Radial - the type of tire construction of nearly every tire on the market.

"15" indicates your rim diameter in inches.

Your vehicle is built and tested based on the manufacturer’s recommendation for tire size. Choosing a different tire size may affect your vehicle’s overall performance and durability.

Weight Rating:

"89" indicates the maximum weight this tire can carry: 1,279 lbs. This is not a number you need to be concerned with when purchasing tires, unless you're pulling or carrying heavy loads.

Speed Rating:

"H" indicates the maximum speed at which this tire can drive: 130 mph. Your vehicle’s tires should be the same or greater than the manufacturer’s recommendations.

Tires with different size designations, constructions, and amounts of wear may affect vehicle handling and stability. For best all-around performance, we do not recommend mixing sizes and types of tires on a vehicle. It would negatively affect the handling characteristics of the vehicle. With winter tires in particular, Transport Canada recommends that tires get changed in sets of four only. It’s safer. That’s why we’ve made it our policy. For more information, view our Winter Tire Policy.

Did you know that each tire on your vehicle has to support a different weight? This unequal weight distribution causes your tires to wear down at different rates. By rotating your tires, you can extend the life of your tires. Check your vehicle owner’s manual for rotation recommendations. If no rotation period is specified, a good rule of thumb is to rotate your tires every 10,000 kilometres.

In one month, a tire can lose quite a bit of air pressure. Check your tire pressure at least twice a month. Air pressure increases with heat, so be sure to measure it before driving, while the tires are still cold. When the weather gets cold, check your tires outside to get the most accurate reading. If you store your vehicle in a heated garage and check the pressure inside, your air pressure reading could be up to 25% higher than the actual pressure. Refer to your owner’s manual to determine how much pressure (or PSI) your tires need, and use a tire gauge to get an accurate reading.